Electrophysiology Daymar College. Lisa H. Young, RN, BSN, MAE 2011

Transcription

1 Electrophysiology Daymar College Lisa H. Young, RN, BSN, MAE 2011

2 Electrical Conduction Pathway

3 Chemical Basis for Impulse Formation

4 Cardiac Action Potential Phases

5 Electrical Pathway ECG Waveforms

6 Systole and Diastole ECG Waveforms

7 Leads

8 Einthoven s Triangle

9 MCL1 and MCL6

10 Leadwire Systems

11 Common Monitor Problems Artifact False-high rate Weak signals Wandering baseline Fuzzy baseline (electrical interference) Baseline (no waveforms)

12 Common Arrhythmia Interferences

13 Normal Sinus Rhythm Rhythm: Regular Rate: bpm P wave: Small, round, before QRS (sinus) PRI: seconds QRS: < 0.12 seconds

14 ECG Paper Each small box is one millimeter (1mm) Each large box (5 small boxes) is 5 millimeters Standard paper speed is 25mm/second Each small box is 0.04 seconds Each large box is 0.20 seconds Convert seconds to milliseconds 1000 X number of boxes in seconds 0.04 sec. = = 40 ms

15 Sinus Bradycardia Rhythm: Regular Rate: bpm P wave: sinus PRI: sec QRS: <0.12 sec Treatment Drugs: Atropine Epinephrine Intervention: Pacer

16 Sinus Tachycardia Rhythm: Regular Treatment Rate: bpm Treat cause, i.e. fever P wave: sinus PRI: sec QRS: < 0.12 sec

17 Sinus Arrhythmia Rhythm: Irregular Treatment Rate: Usually not necessary. P wave: sinus PRI: seconds QRS: <0.12 seconds

18 Sinus Arrest Rhythm: Irregular Treatment Rate: or < 60 Pacemaker P wave: sinus, absent in pause PRI: sec., absent in pause QRS: <0.12 sec., absent in pause

19 ESCAPE BEATS Sinus Escape Beat Junctional Escape Beat Ventricular Escape Beat

20 SINUS BLOCK Rhythm: Irregular Treatment Rate: or < 60 None P wave: sinus, absent in pause PRI: sec., absent in pause QRS: < 0.12 sec., absent in pause

21 WANDERING PACEMAKER Rhythm: Regular or Irregular Rate: bpm P wave: Change size, shape & direction PRI: < 0.12 seconds, may vary slightly QRS: < 0.12 seconds Treatment: Not usually necessary

22 PREMATURE ATRIAL CONTRACTION (PAC) Rhythm: Regular and irregular because of PAC Rate: Underlying rhythm P wave: Abnormal size, shape and/or direction PRI: or prolonged QRS: < 0.12 seconds Treatment: Not usually necessary

23 Non-conducted PAC Non-conducted P wave, which may occur before, during, or after the T wave preceding the pause. Possible distortion of the slope of the T wave preceding the pause; T wave difference in its height or shape. These are clues showing nonconducted P wave could be hidden in T wave

24 PAC Conduction EARLY A PAC occurring in the rhythm NON-CONDUCTED A premature, abnormally shaped P wave is seen without a QRS ABERRANTLY A PAC with a wide QRS

25 PAC Groupings Bigeminal every other beat is a PAC Trigeminal every third beat is a PAC Paroxsymal abruptly occurring in rhythm PAT Paroxysmal Atrial Tachycardia

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28 ATRIAL TACHYCARDIA Rhythm: Regular Rate: P wave: Abnormal, hidden in T wave PRI: sec. if measurable QRS: < 0.12 sec. Treatment: Vagal maneuvers / Adenosine IV

29 PSVT

30 ATRIAL FLUTTER Rhythm: Regular or irregular Rate: Varies P wave: Flutter waves PRI: Not measurable QRS: < 0.12 seconds Treatment: Coagulation, Cardioversion, Medications

31 ATRIAL FIBRILLATION Rhythm: Grossly irregular Rate: Controlled or Uncontrolled P wave: Fibrillatory waves; Coarse / Fine PRI: Not measurable QRS: < 0.12 seconds

32 P wave features with AV rhythms P wave inverted in Lead II P wave immediately before QRS P wave immediately after QRS P wave hidden in QRS

33 Premature Junctional Contraction (PJC) Rhythm: Regular except premature beat Rate: Underlying rhythm P wave: inverted, before, during or after QRS PRI: Short, <.12 seconds QRS: < 0.12 seconds Treatment: Not required

34 JUNCTIONAL ESCAPE RHYTHM Rhythm: Regular Rate: bpm P wave: inverted before, during or after QRS PRI: Short, <0.12 seconds QRS: <0.12 seconds Treatment: Symptomatic-atropine, pacing, tx cause

35 Accelerated Junctional Rhythm Rhythm: Regular Rate: bpm P wave: inverted before, during or after QRS PRI: Short, < 0.12 seconds QRS: < 0.12 seconds Treatment: Correct the cause if necessary

36 Junctional Tachycardia Rhythm: Regular Rate: bpm P wave: usually hidden in preceding T wave PRI: Short, < 0.12 seconds, if present QRS: < 0.12 seconds Treatment: Correct cause or adenosine if needed

37 First Degree AV Heart Block Rhythm: Underlying rhythm Treatment Rate: Usually sinus Monitor P wave: Sinus Review Drugs PRI: greater 0.20 seconds & constant QRS: < 0.12 seconds

38 2 nd Degree AV Heart Block (Mobitz I or Type I or Wenckebach) Rhythm: Irregular Treatment Rate: Less than Atrial rate Atropine P wave: Sinus Review Drugs PRI: Progressively lengthens until missing QRS (MIA) (PRI after missing QRS is shorter than the last PRI) QRS: < 0.12 seconds

39 2 nd Degree AV Heart Block (Mobitz II or Type II) Rhythm: Regular unless the conduction varies Rate: # impulses conducted (< 60 bpm) P wave: More than # QRS (ratio or variable) PRI: 0.12 sec. or prolonged, but CONSTANT QRS: < 0.12 seconds, but could be wide Treatment: Pacemaker, Dopamine or Epinephrine

40 3 rd Degree AV Heart Block (Complete Heart Block (CHB) ) Rhythm: Regular Rate: bpm (usually) P wave: More p waves than QRS complexes PRI: Varies greatly, no relationship with QRS QRS: < 0.12 if junctional, > 0.12 sec. if ventricular focus Treatment: Pacemaker, atropine (if narrow QRS)

41 Intraventricular Conduction Defect Rhythm: Regular Rate: Usually sinus P wave: Sinus PRI: Normal QRS: Wide, greater than 0.10 sec Treatment: Not necessary

42 Premature Ventricular Contraction (PVC) Rhythm: Irregular due to premature beat Rate: Underlying rhythm P wave: None with PVC PRI: Not measurable QRS: Premature, wide, greater than 0.12 sec T wave is usually opposite direction of R wave Treatment: Not necessary or reversible causes

43 Idioventricular Rhythm (Ventricular Escape Rhythm) Rhythm: Usually regular Treatment Rate: bpm or slower Atropine P wave: Absent Pacemaker PRI: Not measurable QRS: Wide, greater than 0.10

44 Accelerated Idioventricular Rhythm Rhythm: Regular Treatment Rate: bpm No treatment needed P wave: Absent PRI: Not measurable QRS: Wide, greater than 0.10 seconds

45 Ventricular Tachycardia Rhythm: Regular, may be slightly irregular Rate: bpm P wave: None PRI: Not measurable QRS: Wide, greater than 0.12 sec. (T opposite R) Treatment: CPR, Defibrillation, Amiodarone, Epinephrine, Lidocaine (cardioversion with pulse)

46 Torsades de Pointes

47 Ventricular Fibrillation Rhythm: Chaotic, irregular Rate: 0 P wave: Absent PRI: Not measurable QRS: Absent Treatment: CPR, Defibrillation, Epinephrine, Amiodarone, Lidocaine, causes.

48 Ventricular Flutter Rhythm: usually regular Rate: ventricular rate is bpm P waves: None seen PRI: None measurable QRS complex: Very wide, regular Treatment Defibrillation CPR Antiarrhythmics

49 Ventricular Standstill Rhythm: None Rate: Atrial only P wave: Present PRI: Not measurable QRS: Absent Treatment CPR Epinephrine Atropine

50 Ventricular Asystole Rhythm: No rhythm Rate: 0 P wave: None PRI: None QRS: Wide fading until none Treatment CPR Epinephrine Atropine

51 Agonal Wicked Witch is MELTING

52 Pulseless Electrical Activity Rhythm: Fairly regular (not sinus) Rate: bpm P wave: Usually present PRI: Normal QRS: Narrow or Wide Treatment: CPR, Epinephrine, Atropine

53 Indications for Pacing Complete Heart Block Symptomatic type II 2 nd degree AV block Sick sinus syndrome Symptomatic bradycardias with syncope 2 nd degree AV block with episodic ventricular arrhythmias Severe CHF and dilated cardiomyopathy Prevent Atrial fibrillation Hypersensitive carotid sinus syndrome Neurocardiogenic syncope (vasovagle syncope) Long QT syndrome Sleep Apnea

54 Components of Pacing System Pulse Generator Pacing Lead Pacing cable

55 Temporary Pacing Treat symptomatic bradycardia after AMI Treat symptomatic bradycardia after cardiac surgery Hyperkalemia Drug toxicity Before permanent pacemaker implantation in symptomatic patients Bacterial endocarditis Lyme disease Cardiac trauma

56 Types of Temporary Pacemakers Transvenous Epicardial Transcutaneous

57 Transvenous Pacemaker QQYjw6no

58 Epicardial Pacing Cardiac surgery Epicardium One or two atrial or ventricular leads

59 Transcutaneous Pacing

60 Permanent Pacemakers

61 Types of Pacing Single-Chamber Pacing Dual-Chamber Pacing Biventricular Pacing

62 Pacemaker Operation Bipolar Unipolar Asynchronous (Fixed-Rate) Demand

63 Codes for Permanent Pacemakers

64 Pacemaker Functions Capture Strength of stimulus (ma) Pulse width Pacemaker spike Indicated by a wide QRS complex Temporary pulse generators

65 Pacemaker Functions Sensing Millivolts (mv) see intrinsic activity Increase sensitivity decrease mv Decrease sensitivity increase mv Sensitivity threshold testing with temporary pacemakers

66 Pacemaker Functions Stimulation Threshold Testing Temporary pacemakers Minimum pacemaker output for capture Peak threshold Chronic stable threshold Performed each shift

67 Ventricular Paced Rhythm

68 Atrial Pacmaker

69 AV Sequential Pacemaker

70 Pacemaker Malfunctions Loss of capture Inadequate stimulus strength Pacing lead out of position Pacing lead positioned in infarcted tissue Electrolyte imbalances or drug effects Delivery of a pacing stimulus during ventricle s refractory period

71 Undersensing Pacing Malfunctions Asynchronous pacing mode Pacing catheter out of position Intrinsic QRS voltage too low Break in connections, battery failure, or faulty pulse generator Intrinsic ventricular activity occurring during pacemaker s refractory period

72 Pacemaker Malfunctions

73 Pacemaker Malfunctions Oversensing Too sensitive Inhibits ouput Interference from internal and external signals

74 Problems with Pacing

75 Analyzing Paced Rhythms

76 Paced Interval

77 Analyzing Paced Rhythms

78 Pacemaker Rhythm: Regular Rate: Set or own P wave: Present or spike PRI: Normal QRS: Present or spike

79 Sick Sinus Syndrome Rhythm: irregular with sinus pauses Rate: fast, slow or alternating; abrupt changes P wave; varies with changes; may be absent PRI: usually normal; varies with changes QRS: normal; varies with changes

80 Non-Sinus Atrial Rhythm Regular Rate: P wave: inverted before each QRS complex PRI: 0.12 seconds or greater QRS: <0.12 seconds

81 ATRIAL TACHYCARDIA Rhythm: Regular Rate: P wave: Abnormal, hidden in T wave PRI: sec. if measurable QRS: < 0.12 sec. Treatment: Vagal maneuvers / Adenosine IV

82 Multifocal Atrial Tachycardia Irregular Rate 150 to 250 bpm P wave: changing shapes & mixed with T wave PRI: varies QRS: <0.12 Treatment: Adenosine

83 Supraventricular Arrhythmias Supraventricular Arrhythmias Atrial Fibrillation Paroxysmal supraventricular tachycardias (PSVT) AV nodal reentry tachycardia (AVNRT) AV reentry tachycardia (AVRT) -WPW -AV reentry over concealed bypass tract Atrial Tachycardia

84 Types of SVT

85 Arrhythmias from Abnormal Conduction Pathways Definition Clinical Implications

86 Physiology of the Accessory Pathway Kent Bundles James Bundle Mahaim s fibers Atriofascicular bypass tracts Concealed accessory pathway

87 Accessory Pathways

88 Location of Accessory Pathways

89 ECG Characteristics

90 Degrees of Preexcitation None Minimal Less than maximum Maximum preexcitation

91 Degrees of Preexcitation

92 Interpretation of Preexcitation Arrhythmia Obtain 12 Lead ECG Compare with resting or normal ECG Assess PR interval Look for delta wave ECG Characteristics Rate and regularity P waves (P ) PRI QRS

93 Accessory Pathway Arrhythmias RECIPROCATING TACHYCARDIA Circus-movement Tachycardia Reentry tachycardia Orthodromic reciprocating tachycardia

94 Reentry

95 AV Nodal Reentry Tachycardia (AVNRT) AVNRT Dual AV node physiology both fast and slow conduction pathways are present in the AV node rapidly conducting tissue has a long recovery time -fast boat, long wake slow-conducting pathway has a relatively short recovery time -slow boats can follow more closely

96 AVNRT: Initiation of tachycardia

97 AVNRT

98 ORTHODROMIC TACHYCARDIA

99 ANTIDROMIC TACHYCARDIA

100 LOWN-GANONG-LEVINE SYNDROME

101 3 Criteria for LGL Syndrome 1. Short PR interval (0.12second or less) 2. Normal QRS configuration 3. Recurrent paroxysmal tachycardia

102 WOLF-PARKINSON-WHITE

103

104 WOLF-PARKINSON-WHITE

105 WPW ECG CHARACTERISTICS OVERT WPW Regular, bpm P wave: upright, normal, and appearing only before each QRS PRI: less than 0.12 seconds and constant QRS: great than 0.10 sec. in duration; a delta wave, slurred on the initial upstroke or downstroke of the QRS

106 WPW CHARACTERISTICS Non-evident WPW Regular, bpm; tendency for unprovoked PSVT, atrial flutter, or A fib P wave: upright, normal, and appearing only before each QRS PRI: second and constant QRS: 0.10 sec.

107 WPW CHARACTERISTICS CONCEALED WPW Regular, bpm; tendency for unprovoked PSVT. P wave: upright, normal, and appearing only before each QRS PRI: sec and constant QRS: 0.10 second in duration

108 Mahaim s Fibers Right sided muscular bridges Originate below AV node into the ventricular wall Normal PR interval with a delta wave

109 Clinical Significance of Arrhythmias of Abnormal Conduction Pathways ASSESSMENT: Leads I, II, III, V1 and V6 in PSVT Assess Heart Rates Assess Ventricular Rate Assess Ventricular Rhythm Assess for history of onset

110 Proposed Interventions for Arrhythmias of Abnormal Conduction Pathways. Avoid AV nodal blocking agents in preexcitation syndromes Consider Amiodarone and Magnesium Paroxysms of tachycardia: EP testing Consider surgery or transvenous radio frequency catheter ablation

111 Table of Accessory Pathways

112 Romano-Ward syndrome

113 Atrio-Ventricular Dissociation One P wave for each QRS P wave moves in and out of QRS complex

114 Aberrant Ventricular Conduction Abnormal conduction pathway QRS complex that has the appearance of PVC Seen with Atrial Fibrillation and MAT Single beat or as a run of beats MCL1 lead

115 Ashman s Phenomenon Rhythm: irregular Rate: reflects the underlying rhythm P wave: abnormal configuration; unchanged if in the underlying rhythm RPI: commonly changes on the premature beat; if measurable at all QRS: altered configuration with right bundle-branch block pattern

116 Bundle Branch Blocks QRS wider than.12 in duration V1 Incomplete vs Complete

117 Right & Left-sided PVCs Determined by the direction of the QRS complex ECG strip in MCL1 lead PVC negative right ventricle PVC positive left ventricle

118 Interpolated PVC PVC falls close to the middle of 2 sinus QRS complexes No change in R R interval

119 End-diastolic PVC PVC falls at the very end of the sinus p wave PVC will have a sinus p wave & short PRI

120 Hyperkalemia ECG Changes

121 Hyperkalemia EKG Tracing

122 Hypokalemia ECG Changes Flatten T waves U waves merge with T wave ST segment depressed

123 Hypokalemia EKG

124 Hypercalcemia ECG Changes

125 Hypocalcemia ECG Changes

126 ECG Effects of Digoxin

127 Induced Arrhythmias CAD: monomorphic VT and atrial fib. Inferior MI: Bradycardia, sinus block, JR, AJR, AV Blocks, AVR Acute MIs: AT, Aflutter, Vfib Myocardial Ischemia: Vfib, VT, Premature beats Ischemic heart disease: 2 nd AVB and PVCs Acute Anteroseptal MI: 2 nd AVB-type II, RBBB Coronary thrombus: PEA

128 Radiofrequency Ablation AV Node Ablation Pulmonary Vein Ablation

129 Arrhythmias Treated with Ablation AV Nodal Reentrant Tachycardia (AVNRT) Accessory Pathway Atrial fibrillation and atrial flutter Ventricular tachycardia

130 Ablation Procedure

131 Surgical Ablation The Maze procedure Minimally invasive surgical ablation The modified Maze procedure

132 12 Lead EKG Introduction 10 leads = 12 views of the heart 3 Limb leads, 3 augmented leads and 6 chest leads Monitoring for ST segment, T wave and Q wave changes

133 Lecture Resources Huff, Jane. ECG Workout: Exercises in Arrhythmia Interpretation. 5 th edition. Lippincott Thaler, Malcom S. The Only EKG Book You ll Ever Need. Lippincott Williams & Wilkins. Walraven,Gail. Basic Arrhythmias. 6 th edition. Pearson/Prentice Hall. Aehlert, Barbara. ECGs Made Easy. 3 rd edition. Mosby; Elsevier ECG Strip Ease; an arrhythmia interpretation Workbook, Lippincott Williams & Wiilkins Lewis, Kathryn. ECG Practical Applications Pocket Reference Guide, Cengage Learning